Twin Campaigns Compromise Websites to Infect Visitors

By Robert Lemos |
Posted 2013-10-30

A malware campaign has infected at least 40,000 Web pages in the past two weeks with malicious code that could infect visitors' computers with a program that poses as a media player, according to security firm Websense.

The attack, known as GWLoad, compromises legitimate Websites to host malicious code to then be delivered to users. The attack uses social engineering to convince users to install another program and then uses a variety of methods, including locking Web pages until the user clicks on ads, to cash in on its compromise of the victim's computer.

GWLoad is not alone in its success: Websense found that the infrastructure created by the malicious program resembles that of an older campaign, known as CookieBomb, which continues to compromise Websites and infect users. The ability for such malicious infrastructure to exist for years or months is surprising, Alex Watson, director of security research for Websense Labs, told eWEEK.

"It blows my mind that these campaigns have been relevant for so long with minor tweaks to their obfuscation techniques and their delivery methods," he said. "A combination of very small investments in obfuscating code has enabled them to bypass most antivirus systems and continue to exist in the wild."

Both GWLoad and CookieBomb have a significant overlap in the sites that they have infected, suggesting some link between the two campaigns. It's possible that the two infection networks have leased the same botnet for infections, but more likely that they are both using the same attack to find and compromise Websites. A search on Google or the Shodan scanning database would reveal a similar list of vulnerable sites and could explain the overlap.

CookieBomb, the older of the two malware campaigns, primarily focuses on delivering ransomware—malware that locks a victim's computer until they pay money for an unlock code. Over time, the authors of the code have slowly added more anti-analysis techniques, such as obfuscation, to the code, Watson said. GWLoad, on the other hand, uses social engineering to get users to download malicious code that requires they take certain actions, such as click on an advertisement, before continuing.

The move to social engineering to install the malware on a victim's computer continues the exodus of attackers from attempting to exploit vulnerabilities in modern software—an increasingly difficult task—to fooling credulous end users.

"Although most Website injections in the wild redirect to exploit Websites, this dominant campaign seems to shift the focus to using a social engineering technique, rather than exploits, to get unwanted content installed on victims' machines," Websense wrote in its analysis.

The trend toward less reliance on exploitation coincides with the recent arrest of the author of the Blackhole exploit kit and his partner; this suggests that cyber-criminals may quickly try to rebuild alternatives to the Blackhole infrastructure, which had been used to distribute malware, Websense said.